Most clinical assays begin with blood collection in a laboratory setting. The Gates foundation and many others have recognized and attempted to deal with the fact that in much of the world clinical testing is done in a primitive setting. The luxury of having a phlebotomist to draw blood with a laboratory to prepare serum or plasma for analysis is not universal at many points-of-care, even in America. The most significant component of this proposal is that the world will obtain a plasma extraction technology that produces a small, reproducible aliquot of plasma without an energy source or human intervention. Moreover, 2.5 or 6 ?L plasma samples collected in this manner can be transported dry on a collection disc to a central laboratory by courier or mail. The technology proposed to accomplish this is based on blood fractionation by frontal loading of a miniature assemblage of membranes where plasma is transported through multiple membrane layers by capillary action. Blood cells are removed via a combination of adsorption and filtration as plasma migrates to a 6.4 mm diameter collection disc at the bottom of the membrane stack during roughly three min. Stripping (delaminating) the upper, cell bearing membrane layers from the system exposes the plasma loaded collection disc which dries in roughly 10 min. These dried samples can be transported from almost anywhere in to world to a laboratory for analysis within 24 hr. This plasma extraction technology is being developed and validated as component of a mass spectrometry (MS) analysis of vitamin D analogues. As part of the vitamin D test proposed and developed in Phase I, a reagent was developed (SecoSET) that derivatizes vitamin D species with high selectivity. The function of SecoSET is to impart a permanent positive charge to vitamin D species that increases their ionization efficiency in electrospray ionization MS and concomitantly reduces their LOQ.